This film didn't get a theatre showing in the UK, but is on DVD. I wonder if it was turned down for plot inconsistencies? (The Tarot Card Killer story does not make chronological sense)
If you can get past this, what you have is a delightful little comedy with a youthful Scarlett Johansson. charming Hugh Jackman, charismatic Ian McShane, and, yes, a still funny Woody Allen .Plus a host of Brit actors in cameos, lovely location filming and a centrepiece theme of down-to-earth New Yorkers blowing the cobwebs off stiff upper lip aristocrats, who appear grateful for the experience.
Don't take this too seriously and let yourself be swept along by the beauty of London and the benevolent humour of it all (though Sondra Pransky's willingness to hop into bed with a rock star (?) strikes a sour note.)